About maximum voltage levels of the load

To compare the amplifiers for loudness from the impedance, set the required impedance value.

Why is the "volume" expressed in dBV

When you compare amplifiers by loudness, the voltage value, expressed in dBV, should be used. The difference in voltage will show the difference in decibel (dB) between the amplifiers.

The power values in regular mW do not convenient to direct comparison.

The direct comparison by power is only suitable for speaker amplifiers operating with an ultra-low-ohm load. This does not apply to headphone amplifiers where the headphone resistance is higher than 8-16 ohms.

Because of the higher resistance of the headphones, when compare the volume of a musical signal it is necessary to simultaneously take into account the current and voltage limits. The speaker amplifier have limit by current. For the exact difference between the amplifiers in decibel, the power value must be converted into voltage in units of dBV, taking into account the margin by current for the music signal to 12 dB.

If made a comparison simply by power, then the error will reach up to 12 dB. When sorting by volumecomparison, you can see that at the same volume values in dBV, the power values in mW will be different.

ASUS Essence One MKII Muses Edition + Grado PS 1000

With the measured characteristics of the Grado PS 1000, the sensitivity of 108.7 dB/VRMS and the impedance of 34.8 ohms, with the ASUS Essence One MKII Muses Edition the average volume on the music signal of 90 дБ SPL in pure mode (equivalent Class A mode) will be provided. This requires an amplifier with a voltage of 1.3 dBV and a current of 30.5 dB(mA).

ASUS Essence One MKII Muses Edition can provide voltages up to 11.6 dBV and up to a current of 31.7 dB(mA). Due to the current limit, the maximum voltage with a headphone impedance of 34.8 Ohm in pure mode will be 2.6 dBV.

ASUS Essence One MKII Muses Edition with PS 1000 will provide the best sound quality in the volume range from 69.3 to 91.3 dB SPL. Thus, relative the level of 90 dB SPL there is a margin of 1.3 dB above by the volume and 20.7 dB below.

Musatoff HA-4 + Grado PS 1000

With the measured characteristics of the Grado PS 1000, the sensitivity of 108.7 dB/VRMS and the impedance of 34.8 ohms, with the Musatoff HA-4 the average volume on the music signal of 90 дБ SPL in pure mode (equivalent Class A mode) will be provided. This requires an amplifier with a voltage of 1.3 dBV and a current of 30.5 dB(mA).

Musatoff HA-4 can provide voltages up to 14.7 dBV and up to a current of 30.8 dB(mA). Due to the current limit, the maximum voltage with a headphone impedance of 34.8 Ohm in pure mode will be 1.7 dBV.

Musatoff HA-4 with PS 1000 will provide the best sound quality in the volume range from 47.5 to 90.4 dB SPL. Thus, relative the level of 90 dB SPL there is a margin of 0.4 dB above by the volume and 42.5 dB below.

Creative Sound BlasterX AE-5 HP Out + Grado PS 1000

With the measured characteristics of the Grado PS 1000, the sensitivity of 108.7 dB/VRMS and the impedance of 34.8 ohms, with the Creative Sound BlasterX AE-5 HP Out the average volume on the music signal of 90 дБ SPL in pure mode (equivalent Class A mode) will be provided. This requires an amplifier with a voltage of 1.3 dBV and a current of 30.5 dB(mA).

Creative Sound BlasterX AE-5 HP Out can provide voltages up to 14.2 dBV and up to a current of 37.8 dB(mA). Due to the current limit, the maximum voltage with a headphone impedance of 34.8 Ohm in pure mode will be 8.6 dBV.

Creative Sound BlasterX AE-5 HP Out with PS 1000 will provide the best sound quality in the volume range from 55.9 to 97.4 dB SPL. Thus, relative the level of 90 dB SPL there is a margin of 7.4 dB above by the volume and 34.1 dB below.

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